John Locke, an English philosopher, believed that people have natural rights. These rights belong to every human being from birth from God. Theses rights include life, liberty, and property. He also believed that people formed governments to protect their rights. Therefore if a monarch violates their rights, the people are entitled to overthrow the monarch.
Baron de Montesquieu, a French philosopher, argued for the separation of powers, a division of the power of government into three separate branches - executive, judicial, and legislative. This protected people because it kept any individual, such as a Monarch, or group from gaining too much power. This division of power became the basis of the government of the United States.